Final answer:
There are practice-while-you-watch videos available for Comparative Advantage and Foreign Exchange. For manikin to student ratio, 1:1 or 2:1 is recommended for CPR training.
Step-by-step explanation:
For practice-while-you-watch videos, you can watch the following:
- Comparative Advantage video
- Foreign Exchange video
Regarding the manikin to student ratio, it depends on the context. If you are referring to a CPR training or simulation, the American Heart Association recommends a manikin to student ratio of 1:1 or 2:1. However, the ratio may vary in other scenarios.